The present invention relates to a light resolution element for irradiating dental replacement pieces with light to effect the hardening of dental replacement pieces as well as a light hardening device having such a light resolution element.
It has long been known to use a light hardening device for hardening the dental replacement pieces in the mouths of dental patients. A representative approach is disclosed in U.S. Pat. No. 4,063,360. In this conventional solution, a light guiding apparatus guides ultraviolet light to the dental replacement piece and the polymerizable coating thereof is completely hardened by the ultraviolet light.
In order to ensure a satisfactory complete hardening of the corresponding coatings, it is necessary that ultraviolet light in sufficient quantities be guided to all of the regions of the dental replacement piece which are to be completely hardened.
In order to improve the true hardening of the dental replacement pieces, one strives to deliver the greatest possible light intensity in the given frequency range within which the plastic material that is to be hardened has the greatest sensitivity.
It has further been suggested to dispose the light emitting device as close as possible to the dental replacement part as well as to irradiate the dental replacement part from several positions. A solution in which the light source is disposed immediately bordering the dental replacement piece is disclosed in the embodiment shown in FIG. 2 of DE-GM 295 11 927. A solution in which the dental replacement piece is irradiated by light from several positions is described in U.S. Pat. No. 5,800,163.
On the other hand, it is desirable, at the least, to be able to subject those dental replacement pieces to a hardening process by a light emitting device wherein the diameter of the dental replacement piece is greater than approximately half the diameter of the light guiding apparatus. A solution according to U.S. Pat. No. 5,800,163 is not suitable for the treatment of such dental replacement parts and, instead, other types of light hardening devices must be deployed which are characterized in that they irradiate solely one side of the dental replacement piece. The known light hardening device is, at the same time, for all substantial purposes, only deployable for those dental replacement parts which project outwardly and cannot be deployed, in contrast, when inlays or onlays are involved.
The present invention offers a solution to the challenge of providing a light resolution element for a light guiding apparatus which can be deployed universally without having to anticipate disturbances in the handling of complex forms of the dental replacement pieces.
In accordance with the present invention, it is particularly advantageous that the light resolution element is configured as a prismatic body which extends in an obstacle free manner from the front and is not formed with any undercutting. Since the light irradiation path is provided within the prismatic body, disturbances of the light irradiation path by, for example, bridge elements, which would otherwise extend into the light beam path, are foreclosed. In one particular embodiment of the light resolution element of the present invention, the multiple re-orientation of the light beam path in the prismatic body permits a substantial enlargement of the acceptable diameter of the dental replacement piece which can be handled to include, for example, those pieces having a diameter which is substantially equal to the diameter of the light guiding apparatus as well as those pieces, as necessary, having a greater diameter.
In accordance with the present invention, these advantages are obtained by the configuration of a prismatic body having angled surfaces whereby an angled surface through which the light beam path first passes extends outwardly at, for example, an angle of 45xc2x0. In connection with the conventional configuration of prismatic bodies, due to the differing indexes of refraction between the body and air, the light beam path is reflected at the interface between the body and air at an angle of 90xc2x0xe2x80x94that is, radially toward the exterior.
In correspondence with the respective length to which the prismatic body extends toward the outside at that interface, there follows a shifting or offset of the light beams toward the outside, so that the strength of the prismatic body at this location determines the shift toward the outside.
Due to an outside oriented angled surface, whose angle corresponds to the angle of an interior angled surface, the light beam path is again re-oriented into an axis parallel direction. The light beam contacts, immediately before the point or apex of the light resolution element, a further angled surface which extends inwardly so that the light beam path is re-oriented radially toward the interior. The light beam path passes through a border surface between the prismatic body and air in a perpendicular direction so that the degree of reflection approaches zero thereat.
It is to be understood that, in accordance with a particular embodiment of the present invention, it can be provided that a body with a high light transmissivity is used as the prismatic body so that the light transmission losses through the light resolution element are, at most, only in the single digit percentage range. Additionally, in a further advantageous embodiment of the present invention, it can be provided that the angled surfaces each mirror or reflect one another in order to approach a degree of reflection approaching 100%.
From the point of view of a further advantage of the present invention, the light resolution element is connected with the light guiding apparatus such that light is not inadvertently lost. In order to achieve this effect, it is provided that the light resolution element includes a bushing in which the end of the light guiding apparatus is tightly or tautly inserted. In an advantageous embodiment of the present invention, the diameter of the bushing is, in fact, somewhat smaller than the diameter of the end of the light guiding apparatus. The insertion of the light guiding apparatus is facilitated by insertion guiding surfaces and the light resolution element is seated under tension firmly on the light guiding apparatus.
Due to the firm seating between the light resolution element and the light guiding apparatus, the optical orientation of the light beam is additionally assured in the desired manner so that a loss of the light performance need not be feared.
It is to be understood that the firm connection of the light resolution element to the light guiding apparatus can be secured in any desired manner. Thus, for example, it is possible to provide a bayonet connection which secures the light resolution element to the light guiding apparatus.
As required, different elements can be made available, each of which is configured in correspondence with the type of light which will irradiate the dental replacement piece to effect polymerization thereof. The varying lengths of the angled surfaces permit flexible adjustment of the size of the light outlet region at the apex or peak of the light resolution element.
In accordance with a further modified embodiment of the present invention, it is provided that at least a third reflection surface in the front end of the light resolution element is convexly curved. In this connection, it is possible to focus the emitted light in a still stronger manner onto the dental replacement part in order to thereby make possible an improved light output.
In accordance with the present invention, it is particularly advantageous that the light resolution element handles a substantial portion of the light beam emitted from the light guiding apparatus and transfers the light beam to the dental restoration piece and, especially, that the light resolution element of the present invention can also be used, if desired, to perform a light hardening process in the mouth of the dental patient.
In accordance with the present invention, a type of channel extends between the shanks of the U-shaped element which permits a free positioning of the light resolution element.